1789952domain: NAppears in sequencesReversion of y - y^2 + y^4.at n=18A063033Number of (5+2) X (n+2) 0..3 arrays with every 3 X 3 subblock row and diagonal sum equal to 0 2 3 6 or 7 and every 3 X 3 column and antidiagonal sum not equal to 0 2 3 6 or 7.at n=13A252537